"Where did this creature get that material?" This was indeed the issue that the group gathered to find out. A material that could allow anything to hide from their perception was not something that would be allowed to exist, but at the same time they would take it to "study". Each had some selfish reasons for this, after all, they were not sure whether the material had the same effect on Lord-level figures.
Coming for it, was just the most rational reason, and each seemed to have some idea about it but never did anything about it until this guy in the coffin gave them a reason. On the left palm of the Phoenix clan patriarch, a small ball was being held, it was obviously space compressed to the very limit, holding the younger generation.
They could see the situation on the outside more clearly, and this is probably something that the Phoenix clan patriarch did intentionally so that the arrogant individuals could see how humans would unite before benefits.